Architectural paint and stain manufacturers typically distribute premixed paints and stains in a small number of popular colors. To accommodate consumer desires and enable matching of existing painted or stained surfaces, architectural paint and stain manufacturers typically also distribute a set of tintable base paints or stains and several concentrated colorants. These are combined in point-of-sale outlets using colorant dispensing and shaker mixing equipment to make small batch lots of custom-tinted paint or stain in a much larger array of colors than the limited colors available in premixed products.
Owing in part to industry custom and the available colorant dispensing equipment, the custom color systems from different paint or stain manufacturers tend to have somewhat similar components. For example, a typical custom color paint system may employ several (e.g., 2 to 4) tintable base paints ranging for example from a bright white base intended to accept at most a small quantity of colorant (viz., having a relatively small available headspace in the base paint container), to a relatively unpigmented clear base intended to accept a much larger quantity of colorant (viz., in a container initially containing for example about 9-10% less base than the bright white base and consequently having greater available headspace for colorant addition). Base paints or stains may employ various binders (e.g., natural or synthetic resins), binder forms (e.g., solution polymers or latex polymers) and vehicles (e.g., solvent-base or waterborne versions), and may provide various dried surface finishes (e.g., matte, semi-gloss or gloss finishes). Some manufacturers also sell colored base paints (e.g. a red, a blue and yellow colored base) which are intended to be combined with additional colorant(s) when one coat hiding power is desired for strongly-tinted custom paint shades.
Colorants may for example be volumetrically metered from a multiple-colorant manually-operated dispensing station, with 12 paint colorants typically being employed in paint tinting colorant dispensing stations for the U.S. market, and more (e.g., 16 or 24 colorants) sometimes being employed in other markets. The dispensing station may for example include an individual dispensing canister for each colorant, and each dispensing canister may for example include a manually-movable piston whose stroke has been indexed to dispense colorant in minimum 1/48, fluid ounce (0.62 cm3) or 1/96 fluid ounce (0.31 cm3) increments. For example, a manually-operated dispensing station is available from CPS Color Equipment, Inc. as the COROB™ D50 dispenser. It accepts up to 24 colorant canisters and has a minimum 1/48 fluid ounce dispensing capacity. Using such manual equipment, it is difficult accurately to tint small batch volumes. For example, paint stores may be reluctant to sell custom-tinted paints in 1 quart or 1 liter containers and instead may insist on selling only larger quantities such as containers holding at least 1 gallon or 4 liters.
In recent years, point-of-sale outlets have begun to employ automated colorant dispensing machines capable of dispensing colorants in smaller minimum quantities, e.g., in 1/192 fluid ounce (0.153 cm3), 1/384 fluid ounce (0.077 cm3) or 1/1024 fluid ounce (0.029 cm3) minimum dispensing quantities. This has enabled point-of-sale preparation of custom-tinted paints and stains in smaller containers than those previously employed.
Some colorants are made and sold by paint or stain manufacturers, and others are available from specialty colorant suppliers. For example, CPS Color Equipment, Inc. sells the COLOR FUSION™ A (8, 10 or 12 colorants), COLTEC™ (12-16 colorants) and MONICOLOR™ C (16 colorants) lines of pigment dispersions for use in point-of-sale paint tinting applications.
In paint factories, high solids content colorant dispersions or surface-treated pigments may be dispensed gravimetrically into paint batches to prepare premixed paints. For example, CPS Color Equipment, Inc sells the HYDRASPERSE™ D line of pigment dispersions, and BASF Corporation sells the XFAST™ line of powdered paint pigments.